Two prospective cohort studies have identified ABO blood group as a risk factor for the development of heart disease. People with blood groups A, B, or AB were 5-23% more likely to develop coronary heart disease compared with those with O blood type. The study by Dr Meian He from Harvard School of Public Health, Boston, MA included 62 073 women from the Nurses’ Health Study (NHS) and 27 428 men from the Health Professionals Follow–up Study (HPFS) and is published in the September 2012 issue of Arteriosclerosis, Thrombosis, and Vascular Biology.

In the NHS and HPFS, the incident rates of coronary heart disease per 100 000 person–years were 125, 128, 142, and 161 for women with type O, A, B, and AB, respectively, and 373, 382, 387, and 524 for men with type O, A, B, and AB, respectively. Compared with individuals with O blood type, individuals with blood group A, B, or AB had a respective 5%, 11%, and 23% increased risk of developing coronary heart disease in an age–adjusted model.

In non-O individuals, plasma levels of factor VIII-von Willebrand factor (vWF) are approximately 25% higher than in individuals with type O blood type. Elevated levels of factor VIII–vWF have been previously identified as a risk factor for coronary heart disease. The vWF has an important role in hemostasis and thrombosis by mediating platelet adhesion to the vascular wall, especially under high shear stress conditions.